Almost 900,000 people used e-cigarettes to try and kick the habit in 2014, estimates suggest.
A new study has found that 891,000 smokers used an e-cigarette, and not a prescription medicine or behavioural support, in a bid to quit.
Researchers from University College London said 37.3% of the 8.46 million adult smokers in England tried to give up in 2014. Of these, 28.2% used an electronic cigarette to assist them.
Previous studies suggest that using an e-cigarette can increase the chances of success by up to 50% compared with using no support or one of the traditional nicotine products such as gum or skin patches bought from a shop.
The researchers said this raises the long-term success rates from around 5% to around 7.5% and calculated that these increased successes amounted to an additional 22,000 people quitting. These people would have failed their attempt if they had used nothing or a "licensed nicotine product" bought from a shop, according to the study published in Addiction.
Professor Robert West, who led the research team, said "E-cigarettes appear to be helping a significant number of smokers to stop who would not have done otherwise - not as many as some e-cigarette enthusiasts claim, but a substantial number nonetheless.
"There have been claims by some public health researchers that e-cigarettes undermine quitting if smokers use them just to cut down, and that they act as a gateway into smoking. These claims stem from a misunderstanding of what the evidence can tell us at this stage, but this is clearly something we need to watch carefully."
Commenting on the study, professor Peter Hajek, director of the Tobacco Dependence Research Unit at Queen Mary University of London, said "E-cigarettes have a potential to reduce smoking related morbidity and many smokers are successful in making the switch from smoking to vaping.
"Specialist smoking cessation services are currently not offering e-cigarettes and are seeing a marked decline in interest. This is unfortunate, as it is likely that even more smokers would switch to vaping successfully if e-cigarettes were combined with behavioural support that the services provide. Hopefully, findings like this will encourage the services to start offering e-cigarettes as a part of their overall toolkit."